Document Z21KZem1Y9Ew598bVK2y9nO0

388 0. A. SANDEB has been shown that with the increased demands of vigorous exercise, ,b&l(' through the lungs may be increased two and one-half to three times increase in normal artery pressure.50'57 It is doubtful, whether in4\tn|| individual any increase in pressure ever occurs except under conditionals^ stress.60 This physiologic enlargement of the pulmonary arterial tragl interfered with in silicosis by three mechanisms: (J) decrease in actual <}% bed by direct obliteration of blood vessels;68'64 (2) limitation of disteififfl the vascular bed by perivascular fibrosis of arterioles, capillaries,., or,) and (S) vascular spasm secondary to local anoxia-caused ventilatory* tory, or diffusion inadequacy, which appears to be a local anoxic effepi||ni| ated by reflex neurological pathways.68 c. Clinical Approach to the Determination of Disability. The^clip'n proach is obviously limited. The usual disability evaluation must be-'urp in situations where malingering is a frequent factor. Reliance upon qbj.qgul is usually, obligatory, but even with this limitation, clinical observation1? vide valuable information. The presence of wheezing, dyspnea,, or significant. Exercise may elicit one or all of these symptoms, which-mlffl present at rest. Conversely, patients claiming inability to work may-upjl walk with the examiner on the level or up a flight of stairs while ( normal conversation without coughing, gasping, or pausing for breat'j liPi of value of such other physical findings as barrel-chest, wide costal plreim, kyphosis, use of accessory muscles, impaired expansion, movement r(easaonnnannvicnen, impaired _1Ii!_v_^__i_L.dJ.i.i1ll1ae_ s. s.^iin Daire cLc. ardia.G. -dU'l-lDessT-a-bgen(U;stg1ffVtH pulse, and impaired physical sounds in measuring pulmonary einifu;^ shown by Fletcher.59 To quote: "With regard to the clinical diagnqfja.fe sema, my conclusion is that it cannot be made with any confidence^^S single observer) except perhaps in the most advanced cases, so thajj|t^ hope of the clinician being able to diagnose the early stages. For thisihefji to.the objective methods of the physiologist to help him in hia.Aijj|j must be pointed out that disability in silicosis is usually due to empnf|||| d. Roentgenology in the Study of Disability. Roentgenologists determination of disability in silicosis can. be used in two ways: tion of the stage of the disease and (2) detection of the presence;M|fS emphysema. Note: Measurement _of diaphragmatic-exfiiimion-hv-^-i.liai^- " J. G'.'Hickam'and W. H. Cargill, Effect of exercise on cardiac`outfiug^^ffl arterial pressure da.'normal persons and in patienta with cardiovascular disenTM.: emphysema, J. Clin. Invest., 27, 10 (1948). "B, Xi. Riley, A. Himmelstein, H. L. Motley, H. M. Wiener, j.nd,,A,jGah^S chronic pulmonar,y d..i.s..e..a..s..e..,..A...m........J......P...h.0ys1i.olv.,iv1a5s2;., 372 (1948). .vsflSPI-I "G. Liljestrand, Regulation of pulmonary arterial blood pressure, 81,162 (1948). .'.{iZSltM "J. Gough, C. M. Fletcher, J. C. Gilson, and P. D. Oldham, DiscussiojirjgfJjjh pulmonary emphysema, Proc. Roy. Soc. Med., 45, 576-586 (1952). .-.sriilJ*; PULMONARY DUST DISEASES 389 I ^orvSSxpir&tory films appears to be of some -value in determination of forr.cTa' tion-of degree of lung dysfunction with extent of the disease is a njjderable controversy. Wright40 feels that there is a direct correla- !"o,`f'i.rliscrete nodular silicosis is, with rare exception, entirely compatible fi*?f^n'lahg capacity adequate to determine full employment," but that |'':a\eij.hadows" indicate disease that is often seriously disabling. Bruce/ ffl^&fEucher and Wiesinger02 agree that only in Stage III silicosis is "^'^llwty found. Peterson, Peterson and Startup,08 Motley, Lang, Gordon -- ylos^l^and Motley60,84 present evidence to show that there is no correla- radiologic appearance and degree of disability. It is possible to reconilhuiopSacally opposed observed viewpoints by questioning the criteria for pv;m-t||; latter series. Differentiation between dysfunction as opposed to Trfy fulsoys not made. The sufficiency of the allowance made for age and ^Vwllh which some series have been weighted with disabled men are rftfyuc.sljlpn., Probably the ultimate answer will await pulmonary function *Wafge)groups of persons of all ages exposed to silica and similar groups not msiilk unary Function Tests in the Evaluation of Disability. The number Ity-.-oflpulmonary function tests used during the past decade to evaluate vaticosis have been tremendous. It is beyond the scope of this chapter clique of the entire field of pulmonary function. The reader is re- sjA:e^li.excellent-publishe(Lstudies.l?0^l'.?i'?I_D.etails...oLequipment and OTigmdividual tests can be obtained from these sources. For the present eftfSignificant work will be summarized. k|m a study of 600 hard and soft coal miners with pulmonary com- |ffigtpry of many years of exposure inside mines, concluded that: devaluation of the degree of pulmonary function impairment can be made "jngr'physiological teste: (1) Ventilation measurements from spirogram tracings ;y, three-second vital capacity, maximal breathing : capacity and the shape Jurve following a deep breath), (2) the degree of bronchospasm present, (3) oiume and alveolar nitrogen per cent after seven minutes of oxygen breathing, ''SooH oxygen saturation at rest and immediately after step-up exercise, (5) the ion.of 0, A. Sander. _ .... ...... .... .... ? ___ _______ ^ d. Scand., Suppl. 129. IpJuEBef, and Wiesinger, Visch. naturf. Ges. Zurich, 83-92 (1947). "**Son; J. M. Peterson, and C. W. Startup, Lancet, 1, 147 (1931). |(31inical pulmonary physiology II, Ind. Med. and Surg., 22f.'262-267 (1953). pffifeaGournand. and D. W. Richards, Jr., Pulmonary insufficiency^ physiologic ..,;.3|trical-methods:-of-analy3i3,-standard-value3-in-iiormal-b-ubiecte;-M'crfrcim^-27-,-- jftTninrpe, ed., Methods in Medical Research, Vol. II. Year BookJPubliahers, Chi-r. j||jp. Ferrer, D. W. Richards, and A. Coumand, Influence of chronic pulmonary .''1 ' ;'^:,and circulation, Am. J. Med., 10, 719-738 (1951). t J